نتایج جستجو برای: dbh of trees

تعداد نتایج: 21171343  

زبیری, محمود, فقهی , جهانگیر, مروی مهاجر, محمدرضا, نوری, زهرا,

The quantitative description of forest structure can be regarded as one of the most usable working tools in modern forest management.The study aims at analyzing the stand structure in unlogged beech forests using nearest neighbor indices. Data collection was done in compartment 319 with an area about 48 ha in Educational and Experimental Forests of University of Tehran. Species and DBH of all ...

A. Sharifi F. Pourshakouri J. Amini

This research develops an allometric model for estimation of biomass based on the height and DBH of trees in the Hyrcanian forests of Iran. An accurate allometric model reduces the uncertainty of allometric equation in biomass estimation using radar images. In this study, 317 trees were selected randomly from the 4 different dominant tree species for the development of an allometric model cover...

اخوان, رضا, مهدوی, علی, کرمی, طاهر,

In order to evaluate the impacts of oleo-gum resin extraction periodicity on natural regeneration of wild pistachio (Pistacia atlantica subsp. kurdica), three different forest areas in Kurdistan province, west of Iran, were selected based on difference extraction periodicities (regular periodicity, irregular periodicity and without periodicity). Then homogenous unit maps in GIS produced, and on...

2006
Stephen R. Shifley Zhaofei Fan John M. Kabrick Randy G. Jensen

Managers are often concerned about oak mortality in maturing mixed-oak forests, but they often lack explicit information about mortality risk for oaks that differ in species, size, crown class, competitive status, and growth rate. In eastern North America, tree species in the red oak group (Quercus Section Lobatae) are typically shorter lived than those in the white oak group (Section Quercus),...

2016
Eileen V. Carey Ragan M. Callaway Evan H. DeLucia EILEEN V. CAREY RAGAN M. CALLAWAY EVAN H. DELuCIA

We assessed the effect that varying patterns of biomass allocation had on growth of ponderosa pine (Pinus ponderosa) growing in the desert climate of the Great Basin and the montane climate of the eastern Sierra Nevada. Prior work established that desert trees have lower leaf: sapwood area ratios than montane trees (0.104 and 0.201 M2/ cm2, respectively) and proportionally greater stem respirat...

Journal: :caspian journal of enviromental sciences 0

this research develops an allometric model for estimation of biomass based on the height and dbh of trees in the hyrcanian forests of iran. an accurate allometric model reduces the uncertainty of allometric equation in biomass estimation using radar images. in this study, 317 trees were selected randomly from the 4 different dominant tree species for the development of an allometric model cover...

Journal: :جنگل و فرآورده های چوب 0
زهرا نوری دانش آموخته مقطع دکتری-دانشگاه تهران محمود زبیری استاد- دانشکده منابع طبیعی-دانشگاه تهران جهانگیر فقهی دانشیار-دانشکده منابع طبیعی دانشگاه تهران محمدرضا مروی مهاجر استاد - دانشکده منابع طبیعی دانشگاه تهران

this study aims at analyzing spatial pattern and associations of fagus oriantalis lipsky in different vertical classes in intact beech forests. data collection was done in 25 ha plot in gorazbon district of educational and experimental forests of university of tehran. species and dbh of all trees with dbh > 7.5 cm were recorded. the location of each tree was determined using azimuth and distanc...

اسلام‌دوست, جمشید , حسینی , سیدمحسن , سهرابی, هرمز , مرادی, زهرا ,

One of the most important factors in determining the volume of trees is selection of appropriate form factor. In the present study, four different methods of form factor calculation were evaluated for two rapid growth species including Populus deltoides and Taxodium distichum. For this purpose, in each stand, 12 trees per 4 diameter class ranging from 10 to 45 cm in DBH were randomly selected a...

Journal: :محیط زیست طبیعی 0
وحید علی جانی دانشجوی کارشناسی ارشد گروه جنگلداری و اقتصاد جنگل دانشکده منابع طبیعی دانشگاه تهران، ایران جهانگیر فقهی دانشیار گروه جنگلداری و اقتصاد جنگل دانشکده منابع طبیعی دانشگاه تهران، ایران محمود زبیری استاد گروه جنگلداری و اقتصاد جنگل دانشکده منابع طبیعی دانشگاه تهران، ایران محمدرضا مروی مهاجر استاد گروه جنگلداری و اقتصاد جنگل دانشکده منابع طبیعی دانشگاه تهران، ایران

quantifying spatial structure is one of the most important components, describing natural ecosystems and their biodiversity. in this study, a set of indices and functions related to spatial structure using 102 established plots with an area of 1000 m2 were presented. to achieve spatial structure of carpinus-fagus type, a set of indices (clark & evans, uniform angle, shannon-wiener, mingling and...

2012
ANITA K. ROSE

Acorn production varies considerably among oak (Quercus) species, individual trees, years, and locations, which directly affects oak regeneration and populations of wildlife species that depend on acorns for food. Hard mast indices provide a relative ranking and basis for comparison of withinand between-year acorn crop size at a broad scale, but do not provide an estimate of actual acorn yield—...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید